David Cameron confirms at a joint press conference with the Russian president, Vladimir Putin, on Sunday that Britain has not yet made a decision to arm the Syrian opposition. The prime minister claims he has reached agreement with Putin to show support for the US and Russian foreign ministers' peace initiative, when world leaders attend the G8 summit in Northern Ireland on Monday

You will not deny that one does not really need to support the people who not only kill their enemies, but open up their bodies, eat their intestines in front of the public and cameras. Are these the people you want to support? Is it them who you want to supply with weapons? Then this probably has little relation to humanitarian values that have been preached in Europe for hundreds of years.

This is not the moment to send more arms. This is the moment for a total ceasefire, an end to the madness. It is time for the US, Russia, the EU, Turkey, Iran, Saudi and all the players to convene an intergovernmental conference to try to halt the carnage. We can’t use Syria as an arena for geopolitical point-scoring or muscle-flexing, and we won’t get a ceasefire by pressing weapons into the hands of maniacs.

If Washington is ready to negotiate with Iran on nuclear issues, it makes no sense to exclude it from the talks on Syria. [The US should also] accelerate preparations for the conference itself by putting sustained pressure on Syria's rebel forces to come up with a negotiating strategy and take part.